Hopewell Precision Area Contamination

Appendix B - Tables

Table 1Contaminants in GroundwaterNear the Hopewell Precision Area Contamination SiteAll values in micrograms per liter (mcg/L)

Analyte:

Trichloroethene

1,1,1-Trichloroethane

Methyl-tert-butyl ether

Max

250

12

28

Min

0.17

0.22

0.07

Arithmetic Mean

2.0

0.62

0.37

50th Percentile

0.25

0.25

0.25

75th Percentile

0.25

0.25

0.25

95th Percentile

12

2.5

0.68

Number of Detects

58

62

42

Number of Wells Sampled

447

451

450

Percent Detect

13

14

9.3

Table 2Contaminants in Indoor Air Near the Hopewell Precision Area Contamination SiteAll values in micrograms per cubic meter (mcg/m3)

Trichloroethene (TCE)

1,1,1-Trichloroethane (1,1,1-TCA)

Methyl tert-Butyl Ether (MTBE)

Tetrachloroethene (PCE)

Basement

Max

172

17

610

2000

Min

0.39

0.36

0.36

0.47

Arithmetic Mean

3.6

1.2

7.6

7.5

50th Percentile

0.54

0.43

0.58

0.45

75th Percentile

2.4

1.1

2.3

0.68

95th Percentile

17

4.6

23.5

3.4

Number of Homes with Detects

51

55

75

48

Number of Homes Sampled

87

94

97

91

Percent of Homes with Detects

59

59

77

53

First Floor

Max

48

12

140

1200

Min

0.37

0.37

0.36

0.45

Arithmetic Mean

2.2

0.9

5.6

7.6

50th Percentile

0.45

0.36

0.69

0.45

75th Percentile

1.7

0.64

3.24

0.68

95th Percentile

10.2

3.2

28.8

3.2

Number of Homes with Detects

54

43

60

40

Number of Homes Sampled

87

94

97

91

Percent of Homes with Detects

62

45

61

44

Table 3Water Quality Standards/Guidelines and Public Health Assessment Comparison ValuesExceeded by Contaminant Levels Found in Private Water Supply Wellsin the Hopewell Precision Contamination AreaAll values in micrograms per liter (mcg/L)

Contaminant

Maximum Detection

Water Quality Standards/Guidelines

Comparison Values*

New York State

US EPA

Ground Water

Surface Water

Drinking Water

Drinking Water

Cancer

Basis**

Noncancer

Basis**

methyl-tert-butyl ether

28

10a

10a

10

--

10

NYS CPF

230

NYS RfD

1,1,1-trichloroethane

12

5

5

5

5

--

--

1960

US EPA RfD

trichloroethene

250

5

5

5

5

6.1

NYS CPF

10

Health Canada RfD

* Comparison values determined for a 70-kilogram adult who drinks 2 liters of water per day. The cancer comparison value is the water concentration that provides an intake corresponding to an increased lifetime cancer risk of one-in-one million. Non-cancer comparison values assume a relative source contribution of 20%.

Table 4Maximum Detected Air Levels, Indoor Air Background Levels and Public Health Assessment Comparison ValuesExceeded by Contaminant Levels Found in Indoor Air Within the Hopewell Precision Contamination AreaAll values in microgram per cubic meter (mcg/m3)

Contaminant

Maximum Detection

Indoor Air Background Level**

Comparison Values*

New York State Air Guidelines

Cancer

Basis***

Noncancer

Basis***

methyl-tert-butyl ether

610

14

--

3.8

CA EPA UR

8000

CA EPA REL

tetrachloroethene

2000

2.5

100

1

NYS DOH UR

100

NYS DOH RfC

1,1,1-trichloroethane

17

2.5

--

--

--

2200

US EPA RfC

trichloroethene

172

0.46

5

0.3 to 7.8

NYS DOH UR

10

NYS DOH RfC

*The cancer comparison value is the air concentration that provides an intake corresponding to an increased lifetime cancer risk of one-in-one million.